My phone has 4G service (can text and make phone calls), but no internet connection?

My phone is connected to the 4G network and I can send text messages and receive phone calls, but I am unable to use my browser or any other app that requires an internet connection. I have full bars. I have tried restarting the phone, taking the SIM card in and out, going in and out of airplane mode, etc. I have mobile data 'on' in my settings.